Improvement in cryptographic devices



F. S. BALDWIN. Cryptographic Device.

No. 197,199. Patented Nov. 20,1877.

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flaW/K/Y a/ZJ law 2562 UNITED STATES PATENT OFFICE.

FRANK S. BALDWIN, OF ST. LOUIS, MISSOURI, ASSIGNOB TO JOHN L. STANAGE,OF SAME PLACE.

IMPROVEMENT IN CRYPTOGRAPHIC DEVICES.

Specification forming part of Letters Patent No. 197,199, dated November20,1877; application filed ITune 15, 1877.

To all whom it may concern:

Be it known that I, FRANK S. BALDWIN, of St. Louis, in the county of St.Louis and State of Missouri, have invented an Improved MechanicalOryptograph, of which the following is a specification:

It is the object of my invention to furnish a mechanical instrument ordevice to enable persons, through the medium of any of the well-knownways of correspondence, to communicate with each other by cipher, andwhich shall be undecipherable by parties who do not possess thecombination or key.

0f the drawing, Figure l is a top plan of my device. Fig. 2 is across-section.

A is the frame, upon which the constructive parts are mounted. To theframe I secure the outer disk B. This contains upon its face thealphabet, the letters of which are arranged from left to right. (SeeFig. 1.) Alongside of the disk B is a similar disk, O, having also uponits face the alphabet, the letters of which are, however, arranged fromright to left. (See Fig. 1.) The disk 0 is arranged to revolve hence itsouter rim edge laps under the contiguous edge of the outer disk B, andthe inner edge of O is similarly made to lap under the contiguous edgeof the disk D. (See Fig. 2.) The frame A has the recessed bearing,fitted to receive the disk 0. (See Fig. 2.) The disk 0, thus mounted,can be revolved either way, by inserting a stile in any of the holes 0which surround the inner edge of said disk. (See figures.) D, the centerdisk, is secured stationary to the frame A. Upon the face of the disk Dis contained the numerals from 0 to 25, and, further, said disk has aprojecting stop, (I. (All shown in Fig. 1.) The alphabet on the disks B0, also the ciphers on D, are spaced off by radius-lines. (See Fig.1.) Eis the index, which is properly pivoted to the center.

The instrument being thus constructed, its manner of use is as follows:The combination or key is first agreed upon between the partiescommunicating.

be H 1 3 7 9 ll, and supposing the message to be communicated is ReadThis then, first, the message or dispatch is to be transformed intosecret characters or into a cipher. There- Supposing the key to.

fore, H being the initial letter of the key, by referring to the disk 0the letter H will be seen, and the stile is therefore inserted in thehole opposite said letter H, and the disk made to revolve until thestile comes in contact with the stop. By next referring to the alphabet,on the outer disk B is the letter R of the dis patch; and at same time,by referring to the cipher -letter on the revolving disk opposite tosaid letter B is the letter K, which is the secret or cipher-letter,while the R is the true letter. The next figure of the key is 1. Placethe index to 1,'insert the stile in the hole opposite to 1, and revolvethe disk 0 till it is estopped. By now referring to the dispatch, E isthe second letter; find this on the outer disk B, and opposite to saidletter will be cipher-letter W; hence W is the cipher equivalent to E,the true letter. The next figure of the key is 3. Place the index at 3,insert the stile in the hole opposite to 3, and revolve the disk G tillit is estopped. Itefer to the dispatch, and A is the letter to be foundon the outer disk B, and opposite to this, on the disk 0, is the cipherX, which, therefore, stands for A, the true letter. Proceed in the samemanner with 7 9 14 until the dispatch has been converted into thecipher, and it will be found that K W X N O M K X is the cipher for ReadThis, the dispatch. The cipher is therefore sent or communicated to theparty.

In case the message or dispatch is longer etition begin with thenumerals, as the key letter (such as H) is simply to indicate the position for starting.

The party receiving the cipher interprets or deciphers the cipher inprecisely the same manner, thus: Bring the key-letter H opposite thestop; then, by referring to the disk 0 for the letter K, opposite tothis will be seen the letter R on the outer disk. By next moving thedisk 0 one place (corresponding to the figure of the combination) theletter E will be found opposite the cipher-letter WV. By moving the diskthree places farther (corresponding to the second letter of thecombination) the letter A will be found opposite the letter X, the

third cipher-letter. The same method is there than the key the latter isrepeated, but in repmanner as it is written.

(either in writing or deciphering the cipher) is obviated, the sameletters appearing opposite to each other; and for the'samereason-thecipher can be solved in precisely the same,

I do notc'l'aimamtating disk having per-E forations and letters or othercharacters, in combination with a stop and ring, both ringand disk beingprovided with corresponding radial'spacinglines; but

What -I do claim is- 1. The-disk 1), provided with letters or othercharacters, constituting a third series, with relation to and incombination with two' di's'ks,B and G,having the separate alphabetsarranged in inverse order, as and for thepurpose set "forth.

2. The pivoted index or pointer E, in combination with the stationarydisk D having letters in radial spacing-lines, as and for the purposeset forth.

In testimony of said invention I have hereunto set iny hand.

FRANK S. BALDWIN.

Witnesses:

JoHN L. STANAGE, WILLIAM W. HERTHEL.

